class Student{
//私有属性name
         private String name = "bit";

//公有属性age
         public int age = 18;
//不带参数的构造方法
       public Student(){
            System.out.println("Student()");
      }
      private Student(String name,int age) {
            this.name = name;
            this.age = age;
            System.out.println("Student(String,name)");
       }
       private void eat(){
System.out.println("i am eat");
}
        public void sleep(){
            System.out.println("i am pig");
        }
            private void function(String str) {
System.out.println(str);
}
@Override
        public String toString() {
                return "Student{" + "name='" + name + '\'' + ", age=" + age + '}';
       }
}